Department of Orthodontics, Kyung Hee University Dental College, Seoul 130-701, Republic of Korea.
Arch Oral Biol. 2013 Jun;58(6):707-16. doi: 10.1016/j.archoralbio.2012.11.003. Epub 2012 Dec 4.
This study was performed to elucidate the involvement of integrin-FAK (focal adhesion kinase) pathway in compressive stress-induced mRNA expression of macrophage colony stimulating factor (M-CSF), tumour necrosis factor (TNF)-α, receptor activator of nuclear factor κB (RANKL) and osteoprotegerin (OPG) and to further confirm the role of the integrin-FAK complex as a mechanoreceptor in PDL cells.
Periodontal ligament (PDL) cells were obtained from patients having healthy first premolars extracted for orthodontic purposes. Cultured PDL cells were divided into three groups: the control group in which compressive stress was administered; the negative control group in which mechanical stress was administered after transfection of negative control siRNA; and FAK knockdown group in which mechanical stress was administered after FAK siRNA treatment. Compressive stress (2g/cm(2)) was for various time durations (0.5, 2, 6, 24, 48h). Total RNA was collected after the experiment and real-time PCR analysis was performed to determine the mRNA expression levels of M-CSF, TNF-α, RANKL and OPG. Also the supernatant was analysed with ELISA to detect the corresponding cytokine concentrations.
The cells of the control group and the negative control group expressed higher mRNA levels of M-CSF, TNF-α, and RANKL but a lower mRNA level of OPG compared to those of baseline. FAK knockdown cells showed lower mRNA expression levels of M-CSF, TNF-α, and RANKL but a higher mRNA expression level of OPG than that in the control. The OPG mRNA expression level in FAK knockdown cells was even higher than that of baseline. ELISA results showed similar pattern of cytokine concentration changes.
Results of this study indicate that the integrin-FAK pathway regulates compressive stress-induced expression of M-CSF, TNF-α, RANKL and OPG and suggests that the integrin-FAK complex acts as a mechanoreceptor in PDL cells.
本研究旨在阐明整合素-FAK（粘着斑激酶）通路在压迫性应力诱导巨噬细胞集落刺激因子（M-CSF）、肿瘤坏死因子（TNF）-α、核因子κB 受体激活剂（RANKL）和骨保护素（OPG）mRNA 表达中的作用，并进一步证实整合素-FAK 复合物作为牙周膜细胞机械感受器的作用。
从因正畸目的而拔除的健康第一前磨牙的患者中获得牙周膜（PDL）细胞。将培养的 PDL 细胞分为三组：对照组施加压迫性应力；阴性对照组在转染阴性对照 siRNA 后施加机械应力；FAK 敲低组在 FAK siRNA 处理后施加机械应力。施加不同时间（0.5、2、6、24、48h）的压缩力（2g/cm(2)）。实验结束后收集总 RNA，实时 PCR 分析测定 M-CSF、TNF-α、RANKL 和 OPG 的 mRNA 表达水平。同时，用 ELISA 分析上清液以检测相应细胞因子的浓度。
与基线相比，对照组和阴性对照组的细胞表达更高水平的 M-CSF、TNF-α 和 RANKL，但 OPG 的 mRNA 水平较低。FAK 敲低细胞显示 M-CSF、TNF-α 和 RANKL 的 mRNA 表达水平较低，但 OPG 的 mRNA 表达水平较高。FAK 敲低细胞的 OPG mRNA 表达水平甚至高于基线。ELISA 结果显示细胞因子浓度变化的相似模式。
本研究结果表明，整合素-FAK 通路调节压迫性应力诱导的 M-CSF、TNF-α、RANKL 和 OPG 的表达，并提示整合素-FAK 复合物作为牙周膜细胞的机械感受器。
